


Helping out

by Tereox_X



Series: Soulmates [3]
Category: Undertale (Video Game)
Genre: Awkward Boners, Awkward Sexual Situations, Awkwardness, Begging, Boners, Consensual Sex, Consent, Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Ectobiology, Embarrassment, Enthusiastic Consent, Explicit Consent, First Time, Fluff, Fluff and Smut, Kissing, Love, M/M, NSFW, Oral Sex, Sex, Smut, Vaginal Sex
Language: English
Status: Completed
Published: 2019-08-23
Updated: 2019-08-23
Packaged: 2020-09-01 15:14:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,732
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20260165
Author URL: https://archiveofourown.org/users/Tereox_X/pseuds/Tereox_X
Summary: A large part of being Soulmates is helping each other out.





	Helping out

**Author's Note:**

> This fanfiction was written as a roleplay collab between xXUndertale_loverXx (X) and SkylerSkyhigh (Sky).
> 
> ~Roles~  
Killer, Cross, Horror, Dust - X  
Nightmare - Sky  
Edit - X
> 
> We hope you'll enjoy! ^^

Nightmare grumbled in frustration as he walked out of his room. His shorts had a noticeable bulge from a wet dream he'd had and he was heading to the bathroom for a cold shower. He hated it when this happened.

Killer looked up when he noticed Nightmare trudging past his room. He didn't look happy...

Killer got up and walked after Nightmare.

"Are you okay?" He asked worriedly.

Cross looked up from his drawing when he heard that. Was someone not okay?

Nightmare looked up at Killer, mid rubbing his skull and a deep flush on his face.

He nodded. "Yeah, I'm fine. Just need a quick shower." He grumbled in annoyance. The bulge was really uncomfortable.

Killer tilted his skull in confusion when he saw the flush.

"Do you have a fever or are you extremely flustered?" He asked with a concerned frown.

Cross peeked out of his room. Was Nightmare okay?

Nightmare flushed deeper. He really didn't want to tell them that he had a boner.

"Um.... I'm fine." Nightmare replied in embarrassment. "The latter. I'll be fine after a shower."

Killer frowned slightly. He had the feeling that Nightmare wasn't telling him everything.

"So..." Nightmare drawled before trying to slip away. It was really awkward for him to try and tell his mates that he had a really uncomfortable boner and that he needed a shower.

Killer stared at Nightmare intently.

"You're not telling us something." He said, knowing that Cross was standing behind him.

"It's not important." Nightmare said, his eye flicking over to Cross who was blocking his path. Great. He began to step back and hopefully go around them.

"Nightmare. If it's affecting you then it is important." Killer replied.

Cross frowned worriedly.

Nightmare hunched in on himself slightly, looking away in embarrassment. This was not something he'd want to tell his mates at all. He was not even sure if they were okay with anything sexual and he didn't want to find out right now after having a wet dream and having a big problem. "It's not a big deal. I'll be fine after a shower."

"Are you sure?" Cross asked worriedly.

"I'm sure." Nightmare said and tried to slip away, hissing softly when his summoned cock twitched.

Cross frowned when he saw a bulge in Nightmare's pants. Was that...?

He blushed brightly. Oh. Oh....

Killer noticed Nightmare's predicament at the same time.

Nightmare flushed deeper when they noticed his problem. "Y-yeah. So can I go now?"

Killer looked up at Nightmare.

"Um... Do you... do you need help...?" He asked hesitantly.

Nightmare shook his skull quickly, feeling more embarrassed by the second. "N-no. I can handle it."

Cross blushed brightly at the thought of helping Nightmare.

"Are you sure?" Killer asked, his cheek bones flushed brightly.

Nightmare nodded with a hum. "Y-you don't have to. I'll be fine."

Killer looked away, his cheek bones glowing brightly.

"I want to help you..." He said softly.

"R-really?" Nightmare asked while looking up at Killer, still flushed deeply. "W-why?"

"I... I love you and..." Killer started to explain but trailed off.

"A-and what?" Nightmare said softly. He flushed deeply. He was not sure why Killer would want to help him.

"Well..." Killer started and looked up at Nightmare. "I kinda... want to do that... with you..." He mumbled softly.

Nightmare gulped, feeling a bit heated. He looked away in thought. Did he want to? It was.... not like it was a problem. They were adults and dating. But-

"I've never..." Nightmare trailed off in embarrassment.

"Me neither..." Killer mumbled, glancing away.

Cross was blushing brightly, covering his face with his hands in embarrassment.

"S-so, are we still going to do it?" Nightmare asked nervously.

Killer nodded shyly. He wanted to do it...

"O-okay." Nightmare said softly. He couldn't help but feel excited despite being flustered. "My room?"

Killer nodded, his Soul fluttering a bit in excitement.

"What's happening here?" Horror asked confusedly. He had never seen Nightmare and Killer so flustered.

Nightmare sputtered silently. He looked down shyly. "Um... we were... thinking of... having sex."

Horror's cheek bones flushed brightly. Sex...?

Dust felt his face heat up. Oh... That explained some stuff... Like why Cross' face looked like a tomato.

"I- I'm sorry." Nightmare resisted the urge to run or cover his face. This was so embarrassing. They shouldn't have to do this for him. "I- I'll just shower and do it another time."

"N.. no... It's okay... I want to help you..." Killer replied quietly.

Horror nodded a bit in agreement.

Nightmare kept flushing deeply. "I-if you say so."

"I... I want to.. help too..." Cross mumbled embarrassedly.

Dust nodded a small bit.

"R-really?!" Nightmare asked in shock. They would help him too?!

Cross and Dust nodded, looking down at the floor. Their faces were glowing brightly with their blushes.

"I... I guess we could." Nightmare said. Stars he should control his emotions better. He was the leader! He shouldn't act like this.

But the heat inside his Soul kept growing hotter at the idea and he just wanted it to happen.

Killer nodded a bit. They should go to Nightmare's room...

He took Nightmare's hand and gently led him towards the room.

The others followed in varying stages of embarrassment.

Nightmare let Killer pull him towards his room, face still flushed a bright blue. He gulped silently in anticipation. They were going to do it. They were really going to do it.

Oh stars that made his mind foggy and his cock twitch.

Killer blushed brightly as he opened the door. He didn't really know what to do... How did you do this with five people...?

Nightmare let Killer pull him inside his room, looking at the others nervously. Oh stars how would this go?

Killer lead Nightmare to the bed. He wasn't sure how to do this though...

The others followed them.

"How are we going to do this...?" Horror asked, his face glowing brightly.

"I- I'm not sure." Nightmare admitted with a deep flush. "I can't take you all at once."

"Maybe one by one...?" Cross mumbled quietly.

"Or two and then two again...." Dust threw in with a bright blush.

Nightmare blushed deeply. "L-like... two doing me at the same time."

He could feel his skull heat up and practically smoking. "I don't think I can handle double."

Dust blushed brightly.

"I guess one by one then..." Killer concluded softly.

Nightmare nodded in agreement and looked at his bed with a deep embarrassed flush. "So who's first?"

Killer looked at the others who seemed too embarrassed to even move.

"I.. Me..." He said quietly.

"Okay." Nightmare said and sat down on the bed. He looked at Killer nervously. What should he do?

Killer flushed even brighter and walked towards Nightmare a bit nervously. Maybe he should start with kissing Nightmare to reassure him a bit...?

Nightmare looked up at Killer expectantly, not knowing what to expect and what to do.

Killer sat down next to Nightmare and kissed him gently.

Nightmare leaned into the kiss hesitantly, relaxing a bit. His hands hesitated before grabbing onto Killer's jacket.

Killer blushed brightly as he deepened the kiss.

Nightmare leaned into the kiss and moaned softly, a fog starting to form in his head. Stars it felt different than all the other times Killer had kissed him.

Killer pulled Nightmare closer, curling his tongue around Nightmare's gently.

Nightmare moaned softly and pulled away, panting heatedly at Killer.

"That felt different." he admitted.

Killer pulled back a bit. That had somehow felt really good.

"Good different or bad different?" He murmured softly.

"Good." Nightmare said softly. His legs shifted slightly to brush his hard cock and forming magic.

Should he ask for more? It felt so good. He wanted more. He wanted to feel good.

Should he beg? People liked begging.

"Please, more." he mumbled softly with a deep blush. "T-take me."

Killer blushed brightly. He kissed Nightmare deeply, laying him onto the bed.

Nightmare relaxed with a pleased sigh and leaned back on the bed. He leaned up towards Killer and held his jacket.

Killer kissed Nightmare deeply, licking his mouth gently. He pressed closer.

Nightmare hummed softly at the kiss, feeling his cock twitch. He shifted uncomfortably at the uncomfortable wetness between his legs.

Killer pulled back a small bit.

"Can I...?" He asked softly.

Nightmare nodded eagerly and tried to remove his jacket, frowning in frustration at his position. It was so hard to remove clothes while on his back.

Killer helped Nightmare remove his jacket and shirt. He hesitated for a second and looked up at Nightmare. Was he fine with losing his pants?

Nightmare helped Killer remove his top clothing, blushing when he realized that he had to remove his pants.

Nightmare pushed his pants down, his cock standing straight and his pussy dripping slightly.

Killer blushed brightly and helped Nightmare remove his pants, his own dick materialising in his pants.

He kissed Nightmare again while taking off his own jacket.

Nightmare kissed Killer deeply and helped Killer remove his jacket. He gently rubbed his hands up Killer's chest slowly before pulling away.

He looked up at Killer panting, turning his skull slightly to the side like the pictures he saw online. He hoped this worked to save his embarrassment.

"Take control Killer." he said softly. "I'm yours."

Killer blushed brightly. That was so hot...

He nodded a bit and slowly slid his hand down to Nightmare's crotch. He took Nightmare's dick and gently rubbed it.

Nightmare tried not to squirm too much when Killer's hand moved down. He gasped and jolted at the touch on his cock and tried to hide his face in the sheets, starting to pant softly. Stars that felt good and so sensitive.

Killer slowly gained a bit of confidence and slowly and gently jerked Nightmare off.

Nightmare bit his lip as Killer jerked him off, feeling close to his peak already despite it only being a few minutes. A bead of precum dripping from the head of the cock.

"Is it okay like that?" Killer murmured softly as he jerked Nightmare off.

Nightmare nodded, biting back a moan with a sigh. He bucked his hips slightly into the touch, wanting more despite being so sensitive. "Y-yeah. Keep going."

Killer smiled a bit and did exactly that, twisting his wrist a bit to be able to pleasure Nightmare better.

Nightmare groaned loudly in pleasure. That felt really good.

"I- I'm close..." he warned.

Killer smiled softly and renewed his efforts. He wanted to make Nightmare feel good.

Nightmare panted softly, pleasure clouding his mind as Killer jerked him off.

After a moment, he arched his spine and came.

Killer grinned a bit. He loved that expression on Nightmare. He slowed down a bit before pulling his hand away.

Nightmare laid on his back, panting softly at the high he was on. His eye fuzzy as he looked to the side.

Killer rubbed Nightmare's skull gently with his clean hand.

"Doing okay?" He asked softly.

Nightmare nodded slowly with a hum. He leaned into the touch a bit, feeling sluggish but still having a bit of energy.

He looked at the others who looked embarrassed yet aroused. "Do you want to...?"

"I... Can.. I try something...?" Cross asked shyly.

Nightmare looked at Cross before nodding. He was curious at what Cross had in mind.

Cross blushed brightly as he walked to Nightmare. He kneeled down next to the bed to face Nightmare's pussy.

Nightmare sat up on his elbows to watch Cross, curious.

He flushed when he realized that Cross was facing his dripping and twitching pussy.

Cross hesitantly leaned forward a bit and gave it a hesitant lick. It actually tasted pretty good. Sweet, a bit weird though.

Killer watched Cross with a bright blush. He kissed Nightmare gently.

Nightmare jolted with a yelp at the sudden lick accompanied by pleasure. He wanted to cover his completely flustered face but instead kissed Killer back hesitantly.

Cross looked up at Nightmare curiously before licking his pussy again, this time a bit slower and longer.

A shudder ran up Nightmare's spine and he moaned into Killer's mouth. It felt so good. His pussy twitched and leaked more fluids.

Cross smiled. Moaning was a sign of pleasure. He kept licking Nightmare's pussy gently.

Killer kissed Nightmare deeply.

Nightmare kept moaning and sighing softly into Killer's mouth before pulling away to pant and groan loudly. He unconsciously spread his legs wider to give Cross access.

Killer smiled down at Nightmare.

"Enjoying yourself?" He asked softly.

Cross gently sucked on Nightmare's pussy.

Nightmare jumped and groaned loudly. "Y-yeah. But... Cross, can you... uh.."

Nightmare flushed deeply, struggling to find his words.

Cross stopped for a moment, looking up at Nightmare attentively.

Nightmare gulped and looks away flushed deeply. "Could you.... push inside? Please?"

Cross flushed brightly.

"Su... Sure..." He mumbled softly. He slowly licked Nightmare's pussy before pushing his tongue inside gently.

Nightmare whined softly, blushing bright after he said that. It was really embarrassing.

He arched his spine and cried out loudly at the pleasure.

Killer rubbed Nightmare's skull gently.

Cross did everything as slow as possible, not wanting to overwhelm Nightmare.

Nightmare's pussy clenched around Cross' tongue, juices dripping from his hole. Pleasure shooting up his spine.

Cross hummed softly as he thrusted into Nightmare's pussy a bit.

Nightmare pushed his pelvis up at the pleasurable vibrations that went through his pussy.

Killer smiled a bit and kissed Nightmare deeply but gently.

Nightmare leaned into the kiss happily, moaning softly into it at the pleasure shooting through him. He could feel a pressure inside his stomach growing tighter and tighter.

Killer rubbed Nightmare's skull gently.

Cross reached his tongue deep into Nightmare.

Nightmare squirmed slightly at the feeling before leaning up towards Killer for reassurance. He was so close. His pussy was fluttering around Cross' tongue.

Killer rubbed Nightmare's sternum gently and nuzzled him softly.

Cross doubled his efforts, thrusting into Nightmare's pussy gently.

Nightmare relaxed at the slow gentle touches from Killer before he cried out loudly in pleasure when Cross' tongue brushed against a sensitive spot inside of him. Juices gushed out of his pussy and around Cross' tongue.

Cross pulled away with a small grin.

Killer rubbed Nightmare's head gently.

Nightmare panted softly, his eyes fuzzy and head heavy. That felt really good.

"Was it good?" Cross asked curiously.

Nightmare nodded slowly, feeling light headed. He closed his eye as he panted. It was like a ringing in his skull and a buzzing in his magic. Not painful or unpleasant. But... good.

Cross smiled and gave Nightmare a gentle kiss.

Nightmare weakly leaned up to kiss Cross back, feeling somewhat satisfied. There was still a burn in his Soul and a feeling that he wanted more. Maybe Dust or Horror?

Cross pulled back after a few seconds and smiled at Nightmare.

Nightmare opened his eye and looked at Cross lustfully. His blue eye fuzzy at the edges.

Cross blushed brightly at that look.

Nightmare groaned softly and sits up, wincing at the liquid dripping from his pussy. While that felt slightly uncomfortable, it was more arousing than anything.

He looked up at the remaining duo. "Do you want your turn?"

Horror flushed deeply but nodded. He really wanted to. And he had to admit that he had a boner now too.

Nightmare looked at Dust who was in a similar state as Horror. "Do you want too?"

Dust nodded, a bright blush lighting up his face.

Horror approached Nightmare and kissed him gently.

Nightmare closed his eye and leaned into the kiss, kissing back passionately.

Horror pulled back after a bit.

"Do you think you could handle.." He trailed off with a bright blush.

Nightmare looked at Horror in confusion. What did Horror want to say? "Handle what?"

Horror covered his brightly flushed face in embarrassment. Well, there went nothing...

"Um... my... my dick......?" He asked quietly.

Nightmare flushed brightly at the question. Him? Taking Horror's dick? As in... fucking? Horror would certainly be big.

Somehow that idea made his pussy wetter.

"S-sure." Nightmare said softly.

Horror looked at Nightmare a bit surprisedly. He smiled slightly.

"I'll do my best to be gentle." He promised.

Nightmare grinned slightly, laying down and put his arms above his head. "What? You think I can't take it?"

He looked at Horror lustfully, feeling confident yet nervous. "Fuck me Horror."

Horror blushed brightly, his dick pulsing in arousal.

"With pleasure~" He purred, taking off his pants.

Nightmare chuckled softly at that. It was so easy to be in control apparently. Even when he was the supposed sub.

Horror moved on top of Nightmare but didn't pin his arms down. From various sparring matches he knew that Nightmare absolutely hated that.

Nightmare looked up at Horror, waiting for his next move. Despite his position, he felt safe and secure under Horror.

Horror smiled and gently guided his dick to Nightmare's opening.

Should he just push in?

Nightmare watched Horror in anticipation, waiting for him to do anything.

Horror pushed in slowly and gently, gasping softly. It felt really good.

Nightmare arched his spine and gasped loudly at the pleasure. It was so good.

Horror paused for a bit, panting in pleasure. He pushed inside a bit more.

Nightmare clenched around Horror's cock with a loud moan. It felt so good. He clenched his hands on the sheets.

Horror gasped out a moan when Nightmare clenched around him. It felt so good.

Dust sat on the bed and rubbed Nightmare's skull gently.

Nightmare shivered slightly before looking up at Dust. He was not getting anything and Nightmare doubted he could handle another round.

"H-Horror.." he groaned out. "Can you t-turn me around?"

Horror blushed.

"Sure." He agreed. He pulled out and turned Nightmare to lay on his front.

Nightmare hissed slightly, feeling a bit sore before looking up at Dust. He reached out and palmed on Dust's dick through his shorts.

"Sorry." Horror apologised. He rubbed Nightmare's spine gently as an apology.

Dust blushed brightly.

"Wha...?" He asked shockedly.

Nightmare grinned at Dust and teased him through his shorts. "You're not getting any attention and it's not fair. So I'm giving you some."

Dust flushed even brighter.

"O.. okay..." He mumbled shyly.

Nightmare grinned, feeling his confidence rise as he reached his hands up to tease Dust's pelvis that wasn't hidden by his shorts.

Dust blushed brightly.

Horror pushed inside Nightmare gently.

Nightmare grunted softly, panting slightly before focusing on teasing Dust slowly. He already looked bothered.

Horror rubbed Nightmare's spine gently and pushed inside a bit more.

Dust moaned softly.

Nightmare moaned softly at the thrust.

He used his two fingers to grab the rim of Dust's shorts before slowly and teasingly pulling it down to his femurs to release Dust's cock.

Dust looked down at Nightmare with a bright blush.

"Do you like it?" Horror asked as he pulled out a small bit to thrust into Nightmare again. It felt so good...

Nightmare grunted and moaned softly. "Yeah..."

Nightmare flushed at the sight of Dust's cock. He hesitantly reached a hand out and wrapped his hand around it.

Dust felt his face heat up some more as he moaned softly.

Nightmare smirked at the moan and rubbed Dust up and down slowly. He panted softly as he felt his pussy clench around Horror.

Dust gasped softly.

Horror groaned when Nightmare clenched around him and thrusted into him gently.

Nightmare quickened his movements, panting softly when Horror thrusted inside of him. He was so close. He looked at Dust's cock nervously when he had an idea and leaned down, hesitantly licking the tip and jumping at the salty taste.

Dust gasped out a moan.

Horror moaned, feeling really close.

Nightmare looked up at Dust before doing it again, feeling a little bit more confident. The salty taste wasn't terrible but wasn't good either.

Dust flushed brightly. He moaned. It felt so good...

Horror kept fucking Nightmare gently.

Nightmare wrapped his lips around Dust's cock head. He used his tongue to lick over the slit, eye focused on Dust's reactions.

Dust moaned in pleasure, his eye lights looking a bit hazy as he looked down at Nightmare.

Horror moaned. He was close already.

Nightmare shuddered in pleasure and sucked Dust's cock, going down the base slowly. He choked when he got halfway and paused, using his tongue to stimulate Dust.

Dust rubbed Nightmare's head gently, moaning in pleasure. It felt so good....

Nightmare closed his eye in content and sucked the cock, licking the slit and the head.

"Night, I'm close..." Dust warned with a moan.

Nightmare looked up before sucking Dust harder and clenching his pussy around Horror.

Horror moaned loudly at the clench.

"Me too..." He mumbled.

Dust gasped loudly before coming hard.

Nightmare jumped when he felt hot salty liquid inside his mouth. He tried to swallow the thick cum.

Dust stared at Nightmare dazedly before gently pulling out.

"Sorry. Are you okay?" He asked worriedly.

Nightmare panted heavily and his tongue poking out, a bit of greyish blue cum sticking to his tongue and mouth.

He nodded dazedly.

Dust blushed brightly.

Horror moaned as he sped up a bit. He groaned loudly, cumming into Nightmare.

Nightmare grunted and hid his face in the sheet before he felt hot cum spurt into him. He groaned as he came after Horror.

Horror pulled out gently, some cum spilling out of Nightmare.

"You okay?" He asked softly.

Nightmare groaned softly and nodded into the sheets. It felt so weird having something warm and sticky leak out of him. It was gross.

Dust rubbed Nightmare's skull gently.

"How does a bath sound?" Killer suggested with a smile.

"It sounds fantastic but I can't move." Nightmare mumbled into the sheets so it was muffled. He was slowly starting to feel sore.

"That's not a problem." Killer replied with a smile. He gently picked Nightmare up bridal style to make sure he wouldn't hurt him and carried him to the bathroom. The others followed happily.

Nightmare flushed at the position and clung onto Killer tightly. It was so odd being at the other side of this treatment. He nuzzled into Killer's shirt.

Killer nuzzled Nightmare gently before kissing him.

Nightmare kissed back slightly with a content sigh. It had been a good first time.

**Author's Note:**

> We hope you enjoyed!
> 
> If you did, please leave a Kudos or even a comment to show us that!
> 
> I hope you have a nice day! ^^


End file.
